The present embodiments relate to a method and system for processing jobs in a print shop where a simulated reconfiguration is performed for at least one autonomous cell in a group of autonomous cells when it is determined that the group of autonomous cells is operating below a desired efficiency level. When the results of the simulation dictate, reconfiguration of at least one autonomous cell occurs. While the present embodiments find particular application in the context of print shop operation, they may also be amenable to other production related applications.
The costs for operating a print shop are generally categorized as the capitalization cost of the printing equipment, and the operating and employment costs for running the equipment. As print shops tend to transform from being lithographic to digital, additional equipment costs will be incurred, so that how the facilities of the print shops are managed becomes even more important to achieve the desired and more profitable operating results.
Print shops face regular pressures to reduce the costs and improve the productivity of their printing processes. This pressure exists whether a print shop is classified as a job print shop, e.g., one producing small-run individual print jobs for customers, a transactional print shop, e.g., one producing statements for a brokerage firm, or a production print shop, e.g., one producing large-run catalogs for mail order businesses. No matter which class a print shop falls into, each print shop operates in essentially the same way. It accepts a digital file, flat sheet stack, bound material or other original as a job input, operates upon this job according to customer instructions, e.g., paper selection, binding, and distribution, and produces a final product which is then transferred and billed to the customer.
The traditional print shop operation is separated into departments, such as data processing and e-prep, printing, finishing, and shipping departments. Each job progresses sequentially through the various departments. Operators are usually trained to operate one piece of equipment. Like pieces of equipment are usually grouped together within each department, and one operator per machine is required for each shift. This configuration produces frequent waste and requires large amounts of inter-shop inventory, which must then be moved from department to department as a job progresses through the print shop. This traditional method of print shop operation causes frequent delays in meeting job delivery dates, increases waste, and takes up a maximum amount of floor space. As a print shop ramps up its production, accurate job production time becomes increasingly difficult to estimate, often resulting in frequent overflow which must be outsourced to other print shops.
The scheduling and flow of jobs through print shops today is typically controlled by preset, often manual, scheduling policies and workflows that take into consideration only the overall equipment, physical layout and labor in the shop. Workflow is typically fixed in a departmental framework. Emphasis is given to keeping all the equipment busy, with the consequence that a lot of work in progress is generated, jobs are often late, error rates are large, and the exact status of specific jobs in progress in the shop is generally not known. Therefore, the productivity of the vast majority of print shops is far from the optimal that can be realized using modern control theory methods to adjust the scheduling, labor, and workflow to respond to both changes in the incoming job flow and to the state of the shop when the jobs are arriving.
Methods exist for improving the operation of the traditional print shop. One method involves re-conceptualizing a traditional print shop as a type of factory process. The print shop itself is then synonymous with the factory plant, and the print job with the manufactured product. Once thus re-conceptualized, commonly known factory flow processes, such as those discussed by Wallace J. Hopp and Mark L. Spearman in Factory Physics (McGraw Hill: New York, 1996) may be adapted to the print shop environment and used to improve the flow of print jobs through the print shop.
In accordance with another method, a print shop may be reorganized into autonomous cells as disclosed in co-pending application Ser. No. 09/706,430, Sudhendu Rai, et al. For each autonomous cell in a corresponding group, resources (e.g., equipment) are grouped together according to different job classes commonly encountered by a specific print shop. The jobs are then broken down into smaller sub-jobs and processed through the cells. Another method to improve operation is to cross-train operators on multiple pieces of equipment. Operators can then be allocated more flexibly as needed throughout the shop. Opportunities also exist to improve scheduling of jobs so as to reduce the amount of inventory and to more fully utilize equipment. An additional option is to improve the layout of equipment on the print shop floor in order to decrease the amount of excess movement required within the print shop. When implemented, these methods have been shown to reduce costs of all classes of print shops by up to twenty percent within six months of implementing the methods.
Although these methods for operational improvement exist, print shop owners are understandably slow to change their traditional methods of operations. One reason for hesitation is that change is typically quite invasive, requiring re-training operators, moving heavy equipment, and learning new habits, all of which equates to down time and lost productivity for the shop during transition. This lost productivity is problematic for a shop owner who must keep the shop operating smoothly throughout transition periods. There is thus little incentive for a print shop owner to make operational changes without having quantitative data showing a positive benefit to bottom-line profits. It is therefore problematic that print shop owners typically have insufficient data to quantify the extent of possible gains available to them by implementing improved operational methods.
Referring to FIGS. 3 and 4, and the accompanying text, of pending application Ser. No. 09/706,430, a print shop is configured for a given job mix by grouping resources into autonomous cells and then determining, with a simulation, whether the cells are suitably arranged. This configuration uses intercellular flow to gage when the autonomous cell arrangement is ready to be fixed in place. Inherent in developing the configuration are certain assumptions regarding job mix. That is, with proper correspondence of autonomous cells to job mix intercellular flow should be minimized. When such correspondence exists, each job, across a significant number of jobs, will be processed within a corresponding autonomous cell so that benefits from small-batch production with associated fast turnaround times (TAT), better quality control, less management overhead and lower work in progress (WIP), can be achieved.
The above approach to configuring the autonomous cells, teaching that cell arrangement is to be fixed upon print shop set-up, can be quite effective as long as job mix remains stable. As job mix changes, however, intercellular flow, among other parameters, can readily exceed an acceptable level. With this increase in intercellular flow, the above-mentioned benefits will inevitably be lost. While a need exists for dynamically reconfiguring the autonomous cells as job mix changes, an ad hoc shuffling of resources (e.g., equipment, software and labor) among autonomous cells can be time consuming and expensive. Moreover, without a rigorous approach for determining the outcome of such shuffling prior to actually doing it, there is no assurance that intercellular flow will even decrease markedly. Hence, it would be desirable to provide a non-intrusive approach for adequately gagging the effect of dynamically reconfiguring a group of autonomous cells prior to actually altering the resource mix among the autonomous cells.